Prognostic Role of Neutrophil to Lymphocyte Ratio in Allergic Rhinitis: A Systematic Review and Meta-analysis

One of the crucial triggers of allergic diseases is an inflammatory reaction and neutrophil to lymphocyte ratio (NLR) is one of the systemic inflammation biomarkers. Our review aimed to evaluate role of NLR in predicting severity and comorbidities of allergic rhinitis (AR). We systematically searched Scopus, Web of Science, and PubMed to find relevant studies. Standardized mean difference (SMD) with a 95% confidence interval (CI) was reported. Due to the high levels of heterogeneity, the random-effects model was used to generate pooled effects. Eleven articles were included in the systematic review, among which ten were included in meta-analysis including 1122 healthy controls and 1423 patients with AR. We found that patients with AR had a significantly higher level of NLR than healthy controls (SMD = 0.19, 95%CI = 0.03-0.36, P = 0.03). In addition, patients with moderate to severe AR had significantly higher levels of NLR compared to those with mild AR (SMD = 0.41, 95%CI = 0.20-0.63, P < 0.001). Interestingly, it was found that NLR could associate with some comorbidities of AR, like asthma. Our results confirmed that NLR could assist clinicians in predicting the severity and comorbidities of AR.